This book presents Maslov's canonical operator method for finding asymptotic solutions of pseudo differential equations. The classical WKB method, so named in honor of its authors: Wentzel, Kramers and Brillouin, was created for finding quasi classical approximations in quantum mechanics. The simplicity, obviousness and "physicalness" of this method quickly made it popular: specialists in mathematical physics accepted it unequivocally as one of the weapons in their arsenal. The number of publications which are connected with the WKB method in one way or another can probably no longer be counted. The alternative name of the WKB method in diffraction problem- the ray method or the method of geometric optics - indicates that the approximations in the WKB method are constructed by means of rays. More precisely, the first approximation of the WKB method is constructed by means of rays (isolating the singular part), after which the usual methods of the (regular) theory of perturbations are applied. However, the ray method is not applicable at the points of space where the rays focus or form a caustic. Mathematically this fact expresses itself in the fact that the amplitude of the waves at such points become infinite.

GENESIS REVISED

"It takes a certain amount of courage to step beyond one’s day-to-day experiments and look at the big picture–and the origin of the Moon is a ‘big picture’ question par excellence. Perhaps it makes sense that William Hartmann, one of the two scientists who unraveled the Moon’s biggest mystery, is not only a scientist but also a part-time artist and science fiction writer. It took someone with an artist’s eye and a fiction writer’s speculative temperament to see the big picture.
"This is a book about that big picture: the origin of the Moon, as interpreted by Hartmann and Alastair Cameron, the second patriarch of ‘The Big Splat.’ It is also about a doomed planet called Theia, and a familiar one called Earth that used to look vastly different from today’s Earth. But, most of all, it is about a long lineage of intellectual voyagers who began exploring the Moon long before Neil Armstrong planted his boot into the lunar dust."
–– From the Introduction

The hugely influential book on how the understanding of causality revolutionized science and the world, by the pioneer of artificial intelligence 'Wonderful ... illuminating and fun to read' Daniel Kahneman, Nobel Prize-winner and author of Thinking, Fast and Slow 'Correlation does not imply causation.' For decades, this mantra was invoked by scientists in order to avoid taking positions as to whether one thing caused another, such as smoking and cancer, or carbon dioxide and global warming. But today, that taboo is dead. The causal revolution, sparked by world-renowned computer scientist Judea Pearl and his colleagues, has cut through a century of confusion and placed cause and effect on a firm scientific basis. Now, Pearl and science journalist Dana Mackenzie explain causal thinking to general readers for the first time, showing how it allows us to explore the world that is and the worlds that could have been. It is the essence of human and artificial intelligence. And just as Pearl's discoveries have enabled machines to think better, The Book of Why explains how we too can think better. 'Pearl's accomplishments over the last 30 years have provided the theoretical basis for progress in artificial intelligence and have redefined the term "thinking machine"' Vint Cerf